Concrete mixer



Oct. 10, 1939. R. M. HOYA CONCRETE MIXER Filed Feb. 11, 1958 4 Sheets-Sheet 1 Oct. 10, 1939. R HOYA 2,175,464

VCONCRETE MIXER Filed Feb. 11, 1938- 4 Sheets-Sheet 2 II/IIIIIIIIIQ wrllllllllllllllllllg ulq u'm mHlll 1 I Fay M15230 Oct. 10, 1939. R M HOYA 2,175,464

CONCRETE MIXER Filed Feb. 11, 1938 4 Sheets-Sheet 5 Oct. 10, 1939. R. M. HOYA 2,175,464

CONCRETE MIXER Filed Feb. 11, 1938 4 Sheets-Sheet 4 Fr. uw PRESSURE Saunas shoved/w J 'j/ A. Ha /a Patented Oct. 10, 1939 UNITED STATES PATENT OFFICE T. L. Smith Company, poration of Wisconsin Application February 11,

14 Claims.

This invention relates to concrete mixers and, while not restricted thereto, is particularly applicable to large mixer units of the type used in central mixing plants where a battery of two or more mixers is often fed from a common source.

In these large installations, it is desirable to employ the so-called front end charging mixers which are those charged and discharged from the same end of the drum, the discharge being effected by tilting the drum. In operation, one mixer is generally being discharged while the others are being charged and mix their contents.

It is desirable in these large mixers, and especially where they are used in a battery, to provide means for looking or holding the mixers in their mixing positions which is usually done by means of some form of mechanical latch. The tilting of the drum is generally effected by some form of fluid pressure operated mechanism; and with a view toward simplicity of handling, this invention contemplates as one of its objects to likewise control the engagement and disengagement of the latch by fluid pressure operated means.

A further object of this invention directed to the same end is to provide means whereby a single control valve controls the functioning of the fluid pressure operated latch and also the fluid pressure operated tilting means.

More specifically it is an object of this invention to provide a novel and improved manner of controlling th'e'latch and the tilting means 'in mixers of the character described whereby upon actuation of a single control valve, theproper sequential operation of first the latch and then the tilting means is effected during tilting of the drum, and vice versa during the return of the drum to mixing position.

In charging the drums of mixers of this character, the dry aggregate is conducted froma central hopper into the mouth of the drum through a charging chute which is mounted to swing from an operative charging position leading to the mouth of the drum to a position remote from the drum and out of the path of the drum contents spilled therefrom upon tilting of the drum.

To improve this charging operation, this invention has as another of its objects to provide a simple but effective manner of sealing the connection'between the mouth of the drum and the discharge end of the charging chute.

Still another object of this invention resides in th'e provision of novelmeansfor introducing the water into the drum,wlu'ch issoldesigned that as Milwaukee, Wis., a cor- 1938, Serial No. 190,013

the water enters the mixing drum it flows around the inner surface of the drum.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, 5 combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed in accordance with the best mode so far devised for the practical appli- 16 cation of the principles thereof, and in which:

Figure l is a view in side elevation of two concrete'mixers constructed in accordance with this invention, arranged in a battery;

Figure 2 is an enlarged side view showing the 20 gelationship of the charging chute and the mixer rum;

Figure 3 is a front view of one of the charging chutes to show particularly the seal for the juncture between thech'arging chute and the mouth of the mixing drumi Figure 4 is a detail view in side elevation of the means for sealing this juncture;

Figure 5 is an enlarged cross sectional view taken through Figure 2 on the plane of the line 55, also showing in detail the manner in which the mouth of the mixing drum is sealed;

Figure 6 is a detail sectional view taken through Figure 3 on the plane of the line 66 p to show the means whereby the water is directed against the inner wall of the mixing drum;

Figure 7 is a view in side elevation, with parts broken away and in section, to show the latch mechanism for holding the drum in its mixing position;

Figure 8 is a view similar to Figure '7, but showing the parts in the positions they assume when the drum is tilted;

Figure 9 is a diagrammatic view to show the manner in which the tilting and latching mechanisms of the two mixers are connected with a fluid pressure source; and

Figure 10 is a detail perspective view of one of the latch elements.

Referring now particularly to the accompanying drawings in which like numerals indicate like parts throughout the several views, the numeral 5 designates a central supply hopper below which two concrete mixers 6 are mounted with their front ends or mouths in position to receive the aggregate conducted thereto by supply chutes I, and to spill their mixed batches into a hopper 8. The supply hopper 5 is provided with gates 9 to control the discharge of the material therefrom, and the charging chutes l are hingedly mounted as at 10 from any suitable support, in position to receive the materials from the outlet ports of the hopper. Water supply pipes II are also provided to conduct water into water passages I2 carried by the supply chutes and positioned to discharge the water into the mixer drums above the dry aggregate.

The two mixers comprising the battery shown are identical in construction, and consequently, a description of one will suffice for both.

The mixer is of the tilting type and has a drum l3 rotatably mounted in a cradle M. The cradle is pivotally supported between spaced pedestals l5 set on a base Hi. The drum is driven by an electric motor I! supported from the tilting cradle and drivingly connected through a suitable transmission (not shown) with a ring gear [8 encircling the drum.

During tilting of the drum from its normal mixing position, which is the position occupied by the mixer shown at the left in Figure 1, to its tilted discharging position, as shown at the right in Figure 1, the charging chute I must be moved or swung clear of the mouth of the drum, and to this end, a frame 19 rigidly attached to the tilting cradle has its outer end connected with the lower end of the charging chute by a link 20. These parts are so proportioned that when the drum is in its mixing position, the charging chute is held in its proper charging position, and as the drum is tilted to discharge its contents, the chute is swung clear of the mouth of the drum, as clearly shown at the right in Figure 1.

During the charging of the mixer, it is desirable to have as close a juncture between the mouth of the drum and the charging chute as possible. To this end, the charging chute protrudes a slight distance into the mouth of the drum, as best shown in Figure 2, and a sealing collar or ring, indicated generally by the numeral 2|, is mounted on the adjacent end of the charging chute to engage the edge of the drum. This sealing collar comprises two half-ring sections 22 and 23 which together comprise an annular flat ring completely encircling the discharge end of the charging chute and of a size to engage with the outer edge of the mixing drum.

The lower half-ring section 22 is mounted from the charging chute by means of an angle iron 24 extending around the lower half of the chute and securely welded or otherwise fixed thereto. The cylindrical flange 25 of this angle iron is of a size to closely fit the inner periphery of the half-ring section 22 so that regardless of its position with respect to the width of the flange 25, a close fit will be maintained between these parts.

The other fiat flange 26 of the angle iron 24 is bored at a plurality of spaced points for the re ception of studs 21. These studs have one end secured to the half-ring section 22 and their other ends project through the holes in the flanges 26 to have tensioning nuts 28 threaded thereon. Coil springs 29 encircling the studs are confined between the half-ring section 22 and'the flange 26 to yieldingly urge the half-ring section outwardly toward the discharge end of the charging chute. Consequently, when the charging chute and drum are in charging relation, the

outer face of the half-ring section 22 engages the edge of the mixing drum.

Inasmuch as the drum rotates and the halfring section 22 is stationary, it is desirable to provide a wear plate 30 which is of the same size and shape as the half-ring section 22 and is secured thereto by bolts for quick replacement.

The upper half-ring section 23 consists merely of a flat band shaped in the form of a half-ring with its inner periphery lying closely adjacent to the upper half of the discharge chute, and like the ring section 22 is of a size to lie fiat against the edge of the drum. This half-ring section 23 is resiliently mounted by means of two spring blades 3!, each anchored to one end of the lower half-ring section 22 and secured to the adjacent end portions of the upper ring section 23.

Consequently, the upper half-ring section is free to flex in the manner shown in dotted lines in Figure 4 during the motion of the charging chute toward and from the mouth of the mixing drum as the mixing drum moves through the final stages of its return to normal mixing position and its initial tilting motion.

With this construction, the introduction of the solid aggregates is accomplished without objec tionable leakage and without having dust blow out through the mouth of the mixing drum.

The introduction of the water into the mixing drum is effected in such a manner that the water entering the drum swirls around the inner wall of the drum. For this purpose, the water passage I2 is mounted on the upper part of a chute in an inclined position, as best shown in Figure 3; and the lower lip 32 of its inner wall curves outwardly, as best shown in Figure 6, and has a plurality of deflecting vanes 33 connecting it with the top of the water passage.

With this arrangement, the water flowing down through the passage l2 discharges into the mixing drum at such an angle as to flow spirally over the inner wall of the mixing drum to thereby insure optimum mixing conditions.

The drum is tilted from one position to the other by fluid pressure operated means comprising a cylinder 34 in which a piston (not shown) reciprocates in response to the application of fluid pressure at one side or the other of the piston. The piston rod 34' which projects from one end of the cylinder is connected to the tilting cradle so that reciprocation of the piston is transmitted to the cradle to tilt the same in one direction or the other. The specific manner in which the connection between the piston rod and the cradle is efie'cted does not form any part of this invention, and therefore has not been shown.

The manner in which the fluid pressure is conducted to the cylinder 34 to eiiect tilting of the drum will be hereinafter described.

It is of course desirable to guard against accidental or unintentional tilting of the mixing drum out of its mixing position. This is especially true where the mixers are used in a battery. Latch means, indicated generally by the numeral 35, are, therefore, provided. This latch mechanism comprises a stop 36 fixed to the cradle and a latch lever 31 having a latching finger 38 to engage over the stop 36 when the cradle is in its mixing position.

The lever 31 is pivotally mounted from a bearing 38 fixed to the stationary frame of the mixer, and as best shown in Figure 10, comprises one integral casting having a front arm 39 and a rear arm 40. The inner ends of these arms terminate in bearings which straddle the. bearing 38 to receive a pivot pin 4!.

The outer end of the front arm 39 is formed, as a bearing 42 and the adjacent opposite portion of the rear arm 50 has an aligned bearing 43. Between the bearings 42 and 43, one end of a toggle comprising hingedly connected levers 44 and 45 is received to be pivotally connected with the lever 31 by a pin 36. The opposite end of the toggle is pivotally supported from a fixed support as at 41. Consequently, upon straightening of the toggle, the latch lever 31 is swung downwardly into position for engagement with the stop 36 and upon collapsing the toggle, the latch lever 3'! is swung to lift its latching finger 38 clear of the stop 36.

The motion of the toggle in its straightening direction is limited by the engagement of a lug 48 on the upper lever 45 with an appropriately formed stop it on the lower lever 44.

Motion is imparted to the toggle by fluid pressure operated means consisting of a cylinder 50 having a piston (not shown) therein which is connected by means of its rod 5| with the knuckle of the toggle. The closed end of the cylinder is pivotally mounted as at 52 from a fixed support so as to permit the same to swing through the are necessary for collapsing and extending the toggle.

The cylinder 58 is connected with the source of fluid pressure to effect the desired motion of its piston upon actuation of a control valve 53 which also controls the functioning of the fluid pressure operated tilting means. Upon actuation of this control valve in one direction, the respective pressure cylinders of the latch actuating and tilting means function sequentially, as will be hereinafter described, to release the latch and then tilt the drum. Actuation of the valve 53 in the other direction effects the return of the drum to its normal mixing position, and during this motion of the drum, response of the latch actuating mechanism is restrained until the drum has reached its mixing position. I

The means for restraining response of the latch actuating mechanism consists of a curved cam track 54 fixed to the tilting cradle with its inner edge concentric to the axis about which the drum tilts. This cam track is so positioned that upon release of the latch, a roller 55 caried by the outer extended end of the rear arm ill of the latch lever is moved inwardly sulficiently to permit the cam track 55 to ride under the roller 55 as the drum is tilted.

The leading end of the cam track during tilting of the drum'from its mixing position isclose to the roller 55 so that as soon as thelatch is released and the tilting motion of the drum begins, the track 55 moves under the roller, thus positively holding the latch against reengagement. The track is long enough so that at any tilted position of the drum, the roller 55 remains in engagement therewith preventing reengagement of the latch.

Hence, while during the return of the drum to its mixing position the fluid pressure operated means for actuating the latch responds earlier than does the fluid pressure operated tilting means, the engagement of the roller 55 with the cam track: restrains the response of the latch actuating mechanism until such time as the drum has been returned to its normal mixing position.

Reference is now had to Figure 9 which shows diagrammatically the manner in which the fluid pressure tilting and the latch actuating means of two mixers are connected with a fluid pressure source.

As here shown, there are two control valves 53, one for each of the two mixers. Each of the control valves is connected with a source of fluid pressure by a. supply line 653 which leads to an inlet port 6| on the valve. Each control valve also has an outlet port 62 which is connected with the fluid pressure source by a return line 63.

The movable element of the control valve is so designed that in one position designated mixing, the inlet port 6| is connected with a fluid conductor 64 which leads to the closed end of the latch actuating cylinder so that fluid pressure applied thereto eflects engagement of the latch.

This fluid conductor 64 also leads to that end of the cylinder 34- at which the application of pressure swings the drum to its mixing position.

It is to be observed, however, that the supply line from the control valve 53 to the cylinder 34 is longer than the line leading to the cylinder 56 so that the piston in the cylinder 53 responds earlier than the piston. in the cylinder 34.

With the movable element of the valve in the mixing position, its outlet port 62 is' connected with another fluid conductor 65 which leads to the opposite ends of the cylinders 55) and 34 to receive the fluid displaced therefrom and conduct it back to the fluid pressure source.

When the movable element of the valve is in its opposite tilting position, as shown at the right in Figure 9, those ends of the cylinders 51] and 3d at which the application of pressure causes release of the latch and tilting of the mixing drum are connected with the fluid pressure source and their opposite ends are connected with the return line.

Hence it will be seen that a single valve controls both the latch and the tilting of the drum, and that the proper sequential operation of these two fluid pressure operated means is obtained in one instance by the increased distance of the cylinder 34 from the pressure source and in the other instance, by the engagement of the roller 55 with the cam track to restrain response of the latch actuating mechanism.

From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art that this invention greatly improves the handling of large concrete mixers, particularly in such installations where a battery of mixers operate together in a central mixing plant.

What I claim as my invention is:

1. In a concrete mixer: a drum; means tiltably mounting the drum; fluid pressure operated means for tilting the drum; a fluid pressure op--, erated latch for holding the drum in a fixed position; and a single control for the latch and the fluid pressure operated tilting means.

2. In a concrete mixer: a drum means tiltably mounting the drum; fluid pressure operated means for tilting the drum; a fluid pressure operated latch for holding the drum in a fixed position; a source of fluid pressure; a single valve for controlling the connection of the tilting means and the fluid pressure operated latch with the source of fluid pressure; and means for insuring sequential operation of the tilting means and latch upon actuation of the control valve.

3. In a concrete mixer: a tilting drum; fluid pressure actuated means for tilting the drum; fluid pressure operated means for holding the drum in a fixed position; a single source of fluid 'pressure; a single control for controlling the connection of the tilting means and the holding means with the source of pressure; and means for delaying the response of one of said fluid pressure operated means until the other has functioned so as to effect sequential operation thereof upon actuation of the single control means.

4. In a concrete mixer: a tilting drum; fluid pressure operated means for tilting the drum; fluid pressure operated means for holding the drum in a fixed position; and means for eifecting sequential operation of said fluid pressure operated means upon connection thereof with a common source of fluid pressure.

5. In a concrete mixer: a tilting drum; fluid pressure operated means for tilting the drum; fluid pressure operated means for holding the drum in a fixed position; a common source of fluid pressure; a valve for controlling the connection of said fluid pressure operated tilting and holding means with the source; and connecting ducts between said valve and the fluid pressure operated tilting and holding means, the connecting ducts to the fluid pressure operated holding means being shorter than those leading to the tilting means so that the holding means responds earlier than the tilting means upon actuation of the valve.

6. In a concrete mixer: a tilting drum; fluid pressure operated means for tilting the drum; fluid pressure operated means for holding the drum in a fixed position; a common source of fluid pressure; a valve for controlling the connection of said fluid pressure operated tilting and holding means with the source; connecting ducts between said valve and the fluid pressure operated tilting and holding means, the connecting ducts to the fluid pressure operated holding means being shorter than those leading to the tilting means so that the holding means responds earlier than the tilting means upon actuation of the valve; and means for restraining actuation of the holding means by its fluid pressure operated means during tilting of the drum in one direction until such tilting motion of the drum has been completed.

7. In a concrete mixer: a tilting drum; fluid pressure operated means for tilting the drum; a latch for holding the drum in a fixed position; fluid pressure operated means for releasing and engaging said latch; a source of fluid pressure; valve means for controlling connection of the fluid pressure operated tilting and latch actuating means with the pressure source; and means so connecting the valve means with the fluid pressure operated tilting means and latch actuating means that the latch actuating means responds earlier than the tilting means upon actuation of the valve means.

8. In a concrete mixer: a tilting drum; fluid pressure operated means for tilting the drum; a latch for holding the drum in a mixing position; fluid pressure operated means for releasing and engaging said latch; a source of fluid pressure; valve means for controlling connection of the fluid pressure operated tilting and latch actuating means with the pressure source; means so connecting the valve means with the fluid pressure operated tilting means and latch actuating means that the latch actuating means responds earlier than the tilting means upon actuation of the valve means; and a mechanical lookout for restraining movement of the latch by its fluid pressure operated actuating means during tilting of the drum from a tilted position back to its mixing position and until the drum reaches said mixing position.

9. In a concrete mixer: a mixing drum; means mounting the drum for tilting movement; a latch for releasably holding the drum in a fixed position; fluid pressure operated means controlled from a single source for sequentially actuating the latch to an inoperative position and then tilting the drum away from its said fixed position and for simultaneously returning the drum back to its said fixed position and tending to restore the latch to its operative position; and means effective as long as the drum is in any but its said fixed position for preventing the restoration of the latch to its operative position whereby the drum is returned to its said fixed position before the latch becomes operative.

10. In a concrete mixer: a tilting drum; means for tilting the drum from and to a predetermined position; a latch for holding the drum in said predetermined position; fluid pressure operated means for actuating the latch from and to operative positions; and means movable with the drum as it tilts and engageable with the latch for holding the same against actuation to its operative position as long as the drum is in any but its said predetermined position.

11. In a concrete mixer: a tilting drum; means for tilting the drum from and to a predetermined position; a latch for holding the drum in said predetermined position; means for actuating the latch from and to its operative position; a cam track movable with the drum as it tilts; and means connected with the latch and engaging said cam track for holding the latch against movement to its operative position as long as the drum is in any but its said predetermined position.

12. In a concrete mixer: a tilting drum; means for tilting the drum from and to a predetermined position; a latch for holding the drum in said predetermined position comprising, a lever pivoted to swing about a fixed axis, and a stop carried by the drum and engageable by a part of said lever; a toggle connected with the lever and adapted upon being straightened out to move the lever to its operative latching position; fluid pressure operated means for collapsing and straightening out the toggle to move the latching lever from and to its operative position; a cam track movable with the drum as it tilts; and means on said latching lever for engaging the cam track to hold the latching lever against movement to its operative latching position except when the drum is in its said predetermined position.

13. In combination: a battery of concrete mixers each having a tilting drum with a charging mouth at one end, said concrete mixers being arranged with the charging mouths of all of the drums in juxtaposition to be capable of receiving aggregates from a common supply hopper; fluid pressure operated means for tilting each mixer drum; fluid pressure operated means for holding each mixer drum in its charging position; a common source of fluid pressure; a single control valve for each mixer; connections tom the common source of fluid pressure to each control valve and the fluid pressure operated means for tilting and for holding each respective drum so that the single control valve for each mixer provides means for controlling the connection of its tilting and holding means with the fluid pressure source; and means connected with each mixer for assuring sequential operation of the fluid pressure operated tilting and holding means; the control valves of all of the mixers being grouped at a central point so that proper sequential charging and discharging oi the mixers may be assured.

14. In a concrete mixer: a tilting drum; means for holding the drum in a predetermined fixed position; power means for tilting the drum away from said predetermined fixed position and retracting it to said position; power means for actuating the holding means; a common power source; manual control means for controlling the connection of both of said power means with the common power source; and means for effecting sequential release of the holding means and tilting of the drum away from said fixed position upon one actuation of said control means, and sequential retraction of the drum to said fixed position and restoration of the holding means to operativeness upon another actuation of said control means.

ROY M. HOYA. 

